<!doctype html>
<html>
	<head>
		<meta charset="utf-8">
		<title>飞机大战</title>
	</head>

	<body>
		<div id="stage" style="margin: 0 auto; width: 480px; height: 650px; text-align: center; vertical-align: middle" >
			<canvas id="canvas" style="border:2px solid red;" width="480" height="650">
				不支持画板对象
			</canvas>
		</div>
		<script>
			//定义名为cal()的方法，包含参数a,b,c.
			function cal(a, b, c) {
				//返回a+b-c的结果.
				return a + b - c;
			}

			//给cal()方法传3个参数.
			//调用cal()方法.
			var iSum = cal(800, 300, 100);
			//在警告框上显示返回的结果.
			alert("结果为" + iSum);
		</script>
	</body>
</html>